Question

Hello, please I need help with this excersice of chemical equilibrum. I really don't get what "1:6" means and how can I use that proportion". The excercise says:
"0,014" moles of HCl are dissolved in water in a proportion of 1:6 (1 mole of HCl per 6 moles of H2O). What is the pH of the solution?

Answer 1

so the concentration of H⁺ from the HCl is ... 1 mole in 6 moles of water

pH is based on moles of H⁺ per liter of solution

water's volume is 18 mL per mole (based on the molar mass)

so 6 moles is 108 mL

so, [H⁺] = 1 mole / .108 L

pH is the negative log of [H⁺]

Answer 2

Hello, thanks to answer my question. .. I was thinking about the answer because it give me a negative pH ... Is that posible? And Does the initial moles of HCl the problem (0,014) interact in something?

Answer 3

I don't think this problem has a simple answer. You can estimate an answer only, I think.
6 mols H2O, as Scott writes, is 108 grams and if we assume the density of H2O is 1.00 g/mL, this then is 108 mL or 0.108 L. However, if we add 0.014 mols HCl to that we don't know the final volume. If we assume adding 0.014 mol HCl doesn't change the volume, then (H^+) = mols/L and that is 0.014/0.108 = approx 0.13
Then pH = -log(0.13) = approx -(-0.9) = 0.9